1. Field of the Invention
The present invention relates to the field of telecommunications, and, more particularly, relates to the connection of one or more transceivers located at a cellular base station to one or more control and radio interfaces, through which the transceivers are operably connected via a trunk to a mobile switching station.
2. Description of Related Art
In a typical cell site configuration, there is at least one trunk that connects the cellular base station, also known as a cell site, to a mobile switching station (MSC). In many cases, this trunk is a DS1 circuit, a four-wire digital circuit composed of twenty-four channels or “time slots” that is commonly referred to as a T1. Each channel of the T1 is capable of handling a single telephone conversation. At the cell site, each T1 is associated with a control and radio interface (CRI). The CRI is responsible for establishing communication between the cell site and the MSC. In this regard, the CRI includes a plurality of Radio Transmitter Termination (RTT) boards, each of which serves as an interface for up to four transceivers. FIG. 1 is a plan view of an exemplary CRI, illustrating a configuration in which there are six RTT boards (as best shown in FIG. 2).
At the cell site, the transceivers are located on cards in a transceiver cabinet. Also located in the transceiver cabinet are Digital Connection (DECON) boards which allow for connection of the transceivers to the CRI, as is further described below. In one common installation, the CRI is connected to three separate transceiver cabinets, each typically housing eight transceivers. In this regard, the twenty-four radios correspond with the twenty-four channels of the T1 (although one transceiver in each cabinet may be used for control functions).
The connection between the transceivers and the CRI in each cabinet is accomplished through CLINK cables. Specifically, each CLINK cable is connected to an RTT board of a CRI at one end and a DECON board associated with a transceiver cabinet at the other end. Each CLINK cable is designed for simultaneous connection of four transceivers in the transceiver cabinet to an RTT board of the CRI.
Since typical transceiver cabinets (for example, the Ericsson RBS 884 Macro product) actually have sixteen slots, by using physically smaller 200 mW transceivers (as opposed to 10 or 30 W radios which each occupy two slots), each transceiver cabinet can accommodate up to sixteen transceivers. Nevertheless, since the CLINK cable is designed for connection of radios in groups of four, adding a single transceiver in the transceiver cabinet would still use up four timeslots (or channels) of the T1 because of the design of the CLINK cable.
Thus, there is a need for an approach that facilitates connection of a single transceiver to an RTT board of a CRI, leaving remaining timeslots associated with the RTT board available for other usage. There is also a need for an approach that facilitates connection of multiple transceivers supported by a common DECON board to more than one RTT board, whether those RTT boards are associated with the same or different CRIs.